1. Field of the Invention
The present invention relates generally to fluid analyzers, and more particularly to a fluid analyzer for measuring the concentration of a sorbate dispersed in a fluid stream.
2. Description of the Prior Art
Many devices are available for detecting concentrations of substances dispersed in a fluid stream. An example of such a device is found in the articles entitled "Using Quartz Crystals as Sorption Detectors" by William H King, Jr., Research/Development, in the April 1969 volume at page 28 and in the May 1969 volume at page 28. The device described therein employs a piezoelectric crystal as a resonator in an electronic oscillator. When the device is placed in a fluid stream, the sorbed mass of a sensed sorbate is accumulated on the crystal, causing the quantity of resonating mass to increase. A disadvantage of such a device is that as the resonating mass increases, the amplitude of a sensed signal may be nonreproducible in the presence of sorbate on the crystal. Other drawbacks of this device are that its sensitivity is limited by the noise of the oscillator and the noise in an associated frequency-sensing discriminator.
Examples of other related prior art detection systems can be found in U.S. Pat. No. 3,260,104, to W. H. King, Jr.; U.S. Pat. No. 3,266,291 to W. H. King, Jr.; U.S. Pat. No. 3,327,519 to H. M. Crawford; U.S. Pat. No. 3,329,004 to W. H. King, Jr.; and U.S. Pat. No. 3,828,607 to D. W. Janzen and C. G. Dell.